Ornithine decarboxylase (ODC) is the initial step in the mammalian polyamine biosynthetic pathway (Pegg and Williams-Ashman, Polyamines in Biology and Medicine, pp. 3-42, Marcel Dekker, New York (1981); Pegg and McCann, Am. J. Physiol. 243: C212-C221 (1982). This enzyme exhibits rapid and many fold changes in activity in response to a wide variety of stimuli and there is evidence that stimulation may be linked to cell growth and tumor promotion (Boutwell et al., Adv. Enzyme Reg. 17: 89-112 (1979)); Russell, Pharmacology 20: 117-129 (1980); Pegg and McCann, (1982 supra.). Detailed studies of the underlying biochemical mechanism of the regulation of ornithine decarboxylase have been hampered by the small amounts of this protein present in mammalian tissues (Pritchard et al., Biochem. Biophys. Res. Commun. 100: 1597-1603 (1981)); Seely et al., Biochem. J. 206: 311-318 (1982) and the consequent difficulty in obtaining the purified protein. Recently, several groups have described the purification of ornithine decarboxylase to homogeneity from rat liver (Kameji et al., Biochem. Biophys. Acta 717: 111-117 (1982)); Kitani, et al, J. Bio. Chem. 258: 235-239 (1983)) or mouse kidney (Persson, Acta Chem Scand. 35: 737-738 (1981); Seely et al., Biochemistry 21: 3394-3399 (1982) and specific antisera have been raised to purified enzyme in rabbits (Persson, Acta Chem. Scand 36: 685-688 (1982)); Seely, et al J. Bio Chem. 258 2496-2500 (1983). However, even from these relatively rich sources of the enzyme, only small amounts of it were obtained and improved methods of isolating the enzyme from crude extracts were needed to study the enzyme in other cell extracts.
Fusion between myeloma cells and spleen cells from immunized donors has been shown to be a successful method of deriving homogenous antibodies. Thus, continuous cell lines of genetically stable hybridoma cells capable of producing large amounts of monoclonal antibodies against maligant tumors and specific viruses and their antigenic determinants have been developed. More particularly, according to U.S. Pat. No. 4,172,124 to Koprowski et al, antibodies demonstrating a specificity for malignant tumors can be produced by somatic cell hybrids between hypoxanthine phosphoriboxyltransferase deficient myeloma cells and spleen or lymph cells derived from an animal previously primed with tumor cells. Also, according to U.S. Pat. No. 4,196,265 to Koprowski et al., continuous cell lines of genetically stable fused cell hybrids capable of producing large amounts of monoclonal antibodies against specific viruses and their antigenic determinants have been developed.
It would be desirable if such cell fusion techniques could be employed to provide a reliable and standard supply of anti-enzyme antibodies, e.g. anti-ODC antibodies, which in turn could be used to react with mammalian ODC, as for example in an immunoaffinity column, from which the active enzyme could then be eluted, recovered and used for the study of polyamine synthesis and its regulation during cell growth.